From EP 002 099, Leidy, for instance, a connection structure for an electrical low-voltage transformer is known, which has a housing made of insulating material and arranged for fastening to the lamination stack of the transformer; accommodated in the housing, as contact means, are a number of electrically conductive contact springs, each of which has an insulation-piercing slit for connection of an external conductor by slit blade insulation piercing connection technology. In addition, the contact springs are provided with a further insulation-piercing slit, likewise forming a slit blade insulation piercing connector, which makes it possible to attach a substantially thinner wire of the coil winding, so as to make an electrically conductive connection between the external conductor and the winding. Assembly is done in such a way that first the housing is secured to the lamination packet, and then the wire ends coming from the winding are inserted into slits in the housing. Next, the contact springs are inserted by pressure from above into corresponding chambers of the housing associated with the slits; on the one hand, this presses the wire ends into the associated insulation piercing slits, and on the other the contact springs are locked in place in the chambers of the housing. In an ensuing step, finally, the external supply line wires can be inserted into the externally accessible insulation piercing slits of the contact springs, As a rule, assembly of the housing and of the contact spring must therefore already be done by the manufacturer of the transformer unit.
In wiring electrical fixtures or luminaires with a three-pole connection clamp for gas discharge lamps, e.g., fluorescent lamps, it was previously necessary to join a considerable number of separate connection points together by their own lines, because the arrangement includes not only a separate connection block, but also additional connection points for capacitors and other necessary accessories. Hence the wiring process is costly and labor-intensive.